node: Ignore non-routable addresses

We ignore addresses that are not globally routable when receiving them
in node announcement message, unless they are coming from a local peer.

radicle-node/src/service.rs

@@ -828,6 +828,7 @@ where
     pub fn handle_announcement(
         &mut self,
         relayer: &NodeId,
+        relayer_addr: &Address,
         announcement: &Announcement,
     ) -> Result<bool, session::Error> {
         if !announcement.verify() {
@@ -1023,6 +1024,7 @@ where
                     timestamp,
                     addresses
                         .iter()
+                        .filter(|a| a.is_routable() || relayer_addr.is_local())
                         .map(|a| KnownAddress::new(a.clone(), address::Source::Peer)),
                 ) {
                     Ok(updated) => {
@@ -1100,12 +1102,13 @@ where
 
         match (&mut peer.state, message) {
             // Process a peer announcement.
-            (session::State::Connected { .. }, Message::Announcement(ann)) => {
+            (session::State::Connected { addr, .. }, Message::Announcement(ann)) => {
                 let relayer = peer.id;
+                let relayer_addr = addr.clone();
                 let announcer = ann.node;
 
                 // Returning true here means that the message should be relayed.
-                if self.handle_announcement(&relayer, &ann)? {
+                if self.handle_announcement(&relayer, &relayer_addr, &ann)? {
                     // Choose peers we should relay this message to.
                     // 1. Don't relay to the peer who sent us this message.
                     // 2. Don't relay to the peer who signed this announcement.

radicle/src/node.rs

@@ -262,6 +262,24 @@ impl From<CommandResult> for Result<bool, Error> {
 #[wrapper_mut(DerefMut)]
 pub struct Address(#[serde(with = "crate::serde_ext::string")] NetAddr<HostName>);
 
+impl Address {
+    /// Check whether this address is local.
+    pub fn is_local(&self) -> bool {
+        match self.0.host {
+            HostName::Ip(ip) => address::is_local(&ip),
+            _ => false,
+        }
+    }
+
+    /// Check whether this address is globally routable.
+    pub fn is_routable(&self) -> bool {
+        match self.0.host {
+            HostName::Ip(ip) => address::is_routable(&ip),
+            _ => true,
+        }
+    }
+}
+
 impl cyphernet::addr::Host for Address {
     fn requires_proxy(&self) -> bool {
         self.0.requires_proxy()

radicle/src/node/address.rs

@@ -50,3 +50,47 @@ impl TryFrom<u8> for AddressType {
         }
     }
 }
+/// Check whether an IP address is globally routable.
+pub fn is_routable(addr: &net::IpAddr) -> bool {
+    match addr {
+        net::IpAddr::V4(addr) => ipv4_is_routable(addr),
+        net::IpAddr::V6(addr) => ipv6_is_routable(addr),
+    }
+}
+
+/// Check whether an IP address is locally routable.
+pub fn is_local(addr: &net::IpAddr) -> bool {
+    match addr {
+        net::IpAddr::V4(addr) => {
+            addr.is_private() || addr.is_loopback() || addr.is_link_local() || addr.is_unspecified()
+        }
+        net::IpAddr::V6(_) => false,
+    }
+}
+
+/// Check whether an IPv4 address is globally routable.
+///
+/// This code is adapted from the Rust standard library's `net::Ipv4Addr::is_global`. It can be
+/// replaced once that function is stabilized.
+fn ipv4_is_routable(addr: &net::Ipv4Addr) -> bool {
+    // Check if this address is 192.0.0.9 or 192.0.0.10. These addresses are the only two
+    // globally routable addresses in the 192.0.0.0/24 range.
+    if u32::from(*addr) == 0xc0000009 || u32::from(*addr) == 0xc000000a {
+        return true;
+    }
+    !addr.is_private()
+        && !addr.is_loopback()
+        && !addr.is_link_local()
+        && !addr.is_broadcast()
+        && !addr.is_documentation()
+        // Make sure the address is not in 0.0.0.0/8.
+        && addr.octets()[0] != 0
+}
+
+/// Check whether an IPv6 address is globally routable.
+///
+/// For now, this always returns `true`, as IPv6 addresses
+/// are not fully supported.
+fn ipv6_is_routable(_addr: &net::Ipv6Addr) -> bool {
+    true
+}